In preceding microelectrode studies the entrainment of respiration by vagal volleys revealed the presence of units in the putamen and basal limbic structures that discharged in phase with respiration. The present neuroanatomical project employing autoradiography and retrograde labeling of neurons with horseradish peroxidase has provided evidence that the parabrachial nucleus (part of the so-called pneumotaxic center) may transmit respiratory-related nerve impulses to some of the forebrain structures in question.